1. Field of the Invention
The present invention relates to apparatuses, methods, and systems for removing sediment from waterway bottoms and pumping the sediment through pipelines. More particularly, the present invention relates to apparatuses, methods, and systems for sediment control and altering the average effective depth in a section of rivers, streams and channels for maintaining the navigability of waterways and coastal restoration.
2. General Background of the Invention
Dredging water-bottoms is a common practice that is normally accomplished by floating vessels located on the water body, such as barges with draglines mounted on deck, or specialized hydraulic dredges like cutter-head suction dredges or hopper dredges. Dredging is mainly utilized for the purpose of maintaining water depth for navigation, but also is used to pump sediments to build or rebuild coastal lands, beaches and etc.
Shoaling of navigational channels is a natural process. Maintaining depth contours in navigational channels in the United States requires significant expenditures by the state and federal agencies (aka U.S. Army Corps of Engineers & etc.) that are responsible for that task. When dredging is being accomplished, the dredges are physically located in the navigational water body in the area that requires dredging. Navigation on the water-body is most often restricted in some way due to the dredging work being done. Sometimes in narrow channels, restriction is severe, and navigational is disrupted in intervals during the course of the dredging operations.
When dredges are employed for maintenance of water depth in a water-body the sediment that is removed may be deposited on-board the vessel such as for hopper barges, or it may be transposed via a mechanical bucket into a deeper area in the water-body usually where there is sufficient current to carry it some distance away, or in the case of a hydraulic suction dredge, it may be put into a pipeline and then deposited any amount of distance away as may be required.
Dredges can also be employed for moving sediment for the purpose of building, rebuilding or filling land. Depending on the type of dredge, the sediment is either hauled on-board, and then moved and deposited at another location or it is put into a hydraulic slurry pipeline that can move water laden sediment scores of miles away.
Coastal land loss is a worldwide problem. Coastal land loss is both a natural process and is often aggravated by man-made alterations to the natural environment. Natural land loss is caused by shoreline erosion caused by normal waves and currents within water-bodies. This type of erosion is further aggravated during natural storms. Natural subsidence of coastal wetlands is also commonly caused by compaction and biodegradation of organic material within the sediment layers under the surface. Man-made causes that can contribute to coastal land loss can include the following: 1) Locks and dams on streams and rivers, 2) placement of levees on rivers and streams for flood protection, 3) jetties on seashores, coastal inlets, rivers, and streams, 4) man-made canals for navigation, coastal development, oil & gas access and pipelines, and etc., 5) extraction of underground minerals, oil, and gas in coastal areas, 6) wakes of marine vessels, 7) sea level rise accelerated by global warming.
A prime example of an area that is experiencing significant coastal land-loss is present day coastal Louisiana. Louisiana has been losing its coastal wetlands at a rate as high as 16,000 acres a year. The rate in 2012 of wetlands loss was estimated to be around 10,600 acres per year. In the 1990's the state had begun addressing the coastal land-loss problem more aggressively. The devastation wrought by hurricanes Katrina, Rita, Gustav, and Ike in the 2005-2008 significantly amplified the need for coastal restoration, and the inter-related issue of coastal flood protection. In response the State of Louisiana developed its “Comprehensive Master Plan for Coastal Restoration and Flood Protection” or “Master Plan”. The Master Plan is a comprehensive conglomerate of projects designed to address the needs for flood protection and wetlands restoration. The latest Master Plan is the 2012 version, and it is to be renewed every 5 years as studies advance the knowledge of the best methods for addressing the problems of coastal wetlands loss and flood protection. The estimated cost to carry out the projects included in the 2012 Master Plan is $50 billion.
The Master Plan includes many projects that will require dredging of sediments for rebuilding barrier islands and marsh creation. Dredging sediments and moving them within a pipeline is a proven way to build/rebuild coastal land. With numerous projects of dredging for marsh creation already completed, there are known cost/benefit figures for this rebuilding option. However, dredging methods, currently used for wetland creation projects, are relatively expensive, with significant fuel cost, labor cost, and mobilization and demobilization costs.
The Master Plan also includes numerous river diversion projects, including “large-scale” river diversions. There is significant and vocal support for these projects, even though sediment diversions are unproven in their ability to build/rebuild land. Proponents for sediment diversions believe that they are superior to dredging, when considering the cost long-term land-building, citing that burning diesel fuel (for dredges) for rebuilding lands is not eco-friendly and unsustainable because it is too costly.
Opponents of river diversions cite that it will take decades if not centuries to restore significant amounts of wetlands. Large-scale river diversions would also cause significant negative impacts and unintended consequences. Diverting large amounts of river water into a brackish-saltwater estuary raises concerns for 1) displacement of traditional fisheries, and critical fisheries habitat, 2) flooding issues for coastal communities, 3) introduction of invasive species, 4) introduction of river-borne pollutants including nutrients from agricultural runoff.
Large-scale river diversions would also have significant unintended consequences on the river channel itself. Diverting river water impacts the hydrodynamics of the river downstream because it takes water away from the traditional river channel, decreasing water velocity downstream. Therefore, river diversions are expected to increase shoaling in down-river areas. This can impact navigation and increase channel maintenance costs.
The current dilemma is that most of the sediments carried by the Mississippi River is wasted and winds up deposited in deep waters of the Gulf of Mexico. The future sustainability of Louisiana's wetlands and the viability of flood protection along the coastal area would be greatly improved if long-term, economical methods were developed for harvesting sediment from the river. An overall goal should be to utilize methods of moving sediment with lower cost while creating less negative unintended consequences. Presently, which of the currently available methods is better is an on-going debate.
It is the intent of the present invention to provide another method that is superior in many ways to currently available methods of harvesting sediments for coastal restoration. A method that is robust, dependable, for long-term harvesting of sediment from a river, such as the Mississippi River. The present invention will be less labor intensive, and environmentally cleaner than diesel-powered dredges, and will have less negative impacts than large-scale river diversions.
The bottom contours of many of U.S. Rivers are being mapped for navigational purposes. The Mississippi River, for example, is mapped and studied extensively by the US Army Corp of Engineers (USACE). Studies by the USACE have shown that burrow areas, where the river has been dredged for sediment removal, have a refill rate of around 80% in one year. The USACE also has computerized modeling programs that predict the effect of changes that affect the river's flow. Predictive computer models can be used to determine best locations for placement of fixed sediment harvesting apparatuses.
The prior art has numerous designs for dredging and sediment removal systems. Prior art teaches many variations in sediment collecting pipes, cells, basins and etc. Also there has been disclosed various methods of evacuating the sediments from the waterway using pump positive pressure or pump suction. The reason that most all of the dredging done today is still done by vessel-based suction dredge is because of its real-world adaptability and robustness in the design. The present invention is novel and unique in that the incorporation of a platform-based pump system gives it robustness, and the design of the mechanical parts gives it redundancy to deal with natural obstacles that cannot be avoided on the bottom of a muddy waterway.
The following references are incorporated herein by reference: U.S. Pat. Nos. 1,197,267; 2,961,782; 3,013,395; 3,591,936; 3,975,842; 4,058,914; 4,149,251; 4,401,576; 4,604,000; 4,711,597; 4,807,373; 4,819,347; 4,830,541; 4,819,347; 4,830,541; 4,943,186; 5,135,579; 5,143,623; 5,285,587; 5,421,105; 6,042,733; 6,112,439; 6,550,162; 7,226,242; 7,591,088; 7,621,059; 7,676,966; 7,850,857; 7,943,039; 8,522,459; U.S. Publication Document Nos.: 2002/0012571; 2005/0211607; 2009/0084735; 2012/0067807; 2013/0022399; PCT Publication Nos.: WO2004/065700; WO2006/107984; WO 2012/153169; WO2013/061006; Foreign Patent Publication Nos.: DE 19904958; EP 1048793; and JP 2005220598.
U.S. Provisional Patent Application Ser. No. 62/044,703, filed 2 Sep. 2014, and U.S. patent application Ser. No. 14/843,511, filed 2 Sep. 2015, are hereby incorporated herein by reference.